JP7378115B2 - Terrain measurement method and markers for terrain measurement - Google Patents

Description

The present invention relates to a topography measurement method for measuring topography, and a topography measurement marker used when measuring topography.

When investigating ancient tombs, it is important to measure their three-dimensional shape. Measuring the three-dimensional shape of ancient tombs has been carried out by flat plate surveying for a long time. However, flat surveying has the drawbacks of requiring a huge amount of human labor and low measurement accuracy. For this reason, in recent years, the three-dimensional shape of a burial mound has been measured by irradiating a laser beam from above the burial mound (for example, see paragraph 0036 of Patent Document 1). However, this method has the disadvantage that it cannot capture the undulations of the earth's surface in areas covered by tree canopies and hidden from the sky. Therefore, aerial measurements using lasers were only used as an aid to on-site surveys, and on-site surveys were still required to accurately measure the three-dimensional shape of kofun.

In view of this situation, the present applicant has proposed a method of measuring the three-dimensional shape of the topography of a burial mound by installing a three-dimensional scanner on the ground (see, for example, Patent Document 2). However, in addition to the undulating surface of the tumulus, there are many obstacles such as trees and weeds on the surface of the tumulus. For this reason, it is not possible to measure the three-dimensional shape of the entire burial mound in one measurement. In this regard, in the topographical measurement method of Patent Document 2, measurements are taken at multiple points using a three-dimensional scanner, and the three-dimensional topographical data obtained from each measurement is combined to cover almost the entire area of the measurement target area, such as a burial mound. I'm trying to get a three-dimensional shape.

Furthermore, as mentioned above, when combining 3D terrain data measured at multiple points, it is necessary to identify the 3D direction of each 3D terrain data. It is necessary to know the coordinates of at least three points in the original terrain data. In this regard, in the topography measurement method of Patent Document 2 mentioned above, the coordinates of one point are determined by using the GPS coordinates of the point where the three-dimensional scanner is installed, and the coordinates of the remaining two points are determined by the point where the marker is installed. By using the GPS coordinates of , the three-dimensional direction in each three-dimensional terrain data is specified.

JP2009-014643A Patent No. 6479718

However, with the terrain measurement method of Patent Document 2, it is not always possible to easily synthesize a plurality of three-dimensional terrain data whose three-dimensional directions are specified.

This is because, in the terrain measurement method of Patent Document 2, in order to connect multiple pieces of 3D terrain data well after the 3D direction is specified, each 3D terrain data is measured using a 3D scanner. When doing this, a sphere called a "sphere" is placed in each measurement range where it overlaps with the adjacent measurement range, and when composing the obtained 3D terrain data, the spheres in each 3D terrain data are Numbering is performed at the reflected locations, and adjacent three-dimensional terrain data are connected so that the same spheres overlap.

However, on 3D terrain data, objects such as round fruits hanging from trees, round signboards erected on the ground, and balls rolling on the ground may be mistakenly recognized as spheres. If such erroneous recognition occurs, the three-dimensional terrain data will not be properly connected. In this case, even if it is known that the sphere is not connected well, it is not possible for a machine such as a computer to identify which sphere has been misrecognized, and a human being can create an image of the three-dimensional topographic data. This is because it requires a lot of effort as it has to be done while actually looking at it.

In addition, with the topography measurement method of Patent Document 2, it may be later discovered that 3D topography data for an area where it was necessary to obtain 3D topography data could not be obtained, and the 3D topography data for that area may Another drawback was that it required a great deal of effort to re-measure the original topographical data using a three-dimensional scanner.

This is because, after completing the terrain measurement method of Patent Document 2, all markers and spheres are usually removed. Therefore, when remeasuring 3D topographic data in an area where 3D topographic data could not be obtained, it is not enough to simply install markers or 3D scanners in the area and take measurements; This is because it is necessary to perform measurements while taking into consideration cooperation with surrounding three-dimensional topographic data, such as the need to arrange the sphere to match the position of the sphere in three-dimensional topographic data.

Furthermore, in the topography measurement method of Patent Document 2, it was necessary to obtain the GPS coordinates of the point where the marker was installed and the GPS coordinates of the point where the three-dimensional scanner was installed. For this reason, markers and three-dimensional scanners had to be installed in areas where the upper part was not covered by tree canopies, making it impossible to perform measurements efficiently in areas with thick trees. In addition, it is not easy to accurately obtain the GPS coordinates of the center of a marker or the center of a three-dimensional scanner.

The present invention was made in order to solve the above-mentioned problems, and provides a terrain measurement method that can easily synthesize a plurality of three-dimensional terrain data. In addition, even if it is later discovered that 3D topographic data for an area that required 3D topographic data was not acquired, the 3D topographic data for that area can be transferred to the 3D scanner. It is also an object of the present invention to provide a topographic measurement method that allows easy re-measurement. Furthermore, it is another object of the present invention to provide a terrain measuring method that does not require a three-dimensional scanner or acquiring GPS coordinates of points where markers are installed. Furthermore, it is also an object of the present invention to provide a topographical measurement marker that can be suitably used when carrying out such a topographical measuring method.

The above issues are
This is a topography measurement method that obtains 3D topography data for almost the entire area in a measurement target area by combining a plurality of 3D topography data D ₁ to D _N (N is an integer greater than or equal to 2) obtained by a 3D scanner. hand,
Three-dimensional terrain data _D1 ,
A marker installation step of installing markers at at least three points P _1.1 , P _1.2 , P _1.3 in the area corresponding to the three-dimensional topographical data D ₁ in the measurement target area;
a marker coordinate acquisition step of acquiring the coordinates of points P _1.1 , P _1.2 , P _1.3 in one coordinate system;
A three-dimensional scanner is installed at a point where all the markers installed at points P _1.1 , P _1.2 , P _1.3 come into view, and the area around the three-dimensional scanner is scanned.
The subsequent three-dimensional terrain data _D2 to _DN are also obtained through the same process as the three-dimensional terrain data _D1 ,
The three-dimensional terrain data D ₁ to D _N are arranged in the first coordinate system based on the coordinates of the markers acquired in the respective marker coordinate acquisition steps when acquiring the three-dimensional terrain data D ₁ to D _N. This problem can be solved by providing a terrain measurement method characterized in that three-dimensional terrain data D ₁ to D _N are synthesized.

Here, the "measurement target area" is a concept that includes the peripheral area of the measurement target. Therefore, for example, when measuring the overall shape of a tumulus, it is not only necessary to place markers on the tumulus that is the object of measurement, but also to place markers in the surrounding area of the tumulus, or both (inside the tumulus and inside the tumulus). It also falls within the technical scope of the present invention to install a marker in the area surrounding the area.

Furthermore, "the subsequent three-dimensional terrain data D ₂ to D _N are also obtained through the same process as the three-dimensional terrain data D ₁ " means, specifically, when n is an integer greater than or equal to 2 and less than or equal to N. To,
Three-dimensional terrain data D _n ,
At least three points P n in the area corresponding to the three-dimensional topographical data D _n in the measurement target area _{. 1} , P _{n. 2} , Pn _. A marker installation process of installing a marker in _{step 3} ;
Point P _{n in one coordinate system. 1} , P _{n. 2} , Pn _. a marker coordinate acquisition step of acquiring the coordinates of ₃ ;
Point P _{n. 1} , P _{n. 2} , Pn _. This means that a three-dimensional scanner is installed at a point where all the markers set in _{step 3} can be seen, and the image is acquired through a scanning process in which the area around the three-dimensional scanner is scanned.

In the topography measurement method of the present invention, _{the directions and positions of a plurality of (N) pieces of three-dimensional topography data D 1 to D N are determined} by the coordinates ( Based on the coordinates of those markers, the three-dimensional terrain data D ₁ to D _N are arranged in a common coordinate system (the first coordinate system). In this way, the three-dimensional terrain data D ₁ to D _N are synthesized. Therefore, by simply giving the coordinates to the reflection points of the markers in the 3D topographic data D ₁ to D _N obtained by measurement with a 3D scanner, the 3D topographic data D ₁ to D _N can be naturally synthesized. This makes it possible to synthesize three-dimensional terrain data D ₁ to D _N without using a sphere. Therefore, it is possible to easily synthesize the three-dimensional terrain data D ₁ to D _N. In addition, when performing measurements using a 3D scanner, there is no need to install a sphere on-site, making it possible to perform measurement tasks efficiently using a 3D scanner.

Further, in the topographic measurement method of the present invention, as described above, there is no need to install a sphere at the site when performing measurement using a three-dimensional scanner. For this reason, even if it is later discovered that 3D terrain data for an area that required 3D terrain data could not be acquired, it is not possible to link with surrounding 3D terrain data. Without taking this into account, if a marker or 3D scanner is appropriately installed in an area where 3D topographic data has not been obtained, it is possible to re-measure the 3D topographic data for that area. Therefore, it is also possible to easily re-measure the three-dimensional topographical data of the area for which it was necessary to obtain the three-dimensional topographical data.

In the topography measurement method of the present invention, the method of acquiring the coordinates of the marker is not particularly limited. The coordinates of the marker can also be obtained by GPS, but in this case, as described above, it becomes difficult to install the marker in a location where it is difficult to obtain GPS coordinates because the top is covered with a tree canopy or the like. However, at least three markers installed in the same area must be installed in locations where all of the markers are within the field of view of the 3D scanner, and the location of the markers may vary to some extent in relation to the 3D scanner. limited. For this reason, if markers are placed while paying attention to the presence or absence of obstacles (such as tree crowns) above, there is a risk that the efficiency of the marker installation work will be significantly reduced. Therefore, it is preferable that the coordinates of the marker be obtained not by GPS but by measurement using transit as described below.

That is,
The marker coordinate acquisition process when acquiring three-dimensional terrain data _D1 is as follows:
a transit installation step of installing a transit in or near an area corresponding to three-dimensional topographical data _D1 ;
a transit coordinate acquisition step of acquiring the coordinates of the point where the transit is installed in the first coordinate system;
A marker coordinate measuring step of acquiring the coordinates of points P _1.1 , P _1.2 , and P _1.3 in the one coordinate system by measurement using a transit;
It is preferable that the subsequent marker coordinate acquisition step for acquiring the three-dimensional topographic data D ₂ to D _N is also performed through the same steps as the marker coordinate acquisition step for acquiring the three-dimensional topographic data D ₁ .

Here, "the marker coordinate acquisition process when acquiring the subsequent three-dimensional terrain data D ₂ to D _N is also performed through the same process as the marker coordinate acquisition process when acquiring the three-dimensional terrain data D ₁ ". Specifically, when n is an integer greater than or equal to 2 and less than or equal to N,
The marker coordinate acquisition process when acquiring three-dimensional terrain data _Dn is as follows:
a transit installation step of installing a transit in or near an area corresponding to three-dimensional topographical data D _n ;
a transit coordinate acquisition step of acquiring the coordinates of the point where the transit is installed in the first coordinate system;
The point P _{n. in the first coordinate system is determined by the transit measurement. 1} , P _{n. 2} , Pn _. This means that it is carried out by passing through the marker coordinate measurement step of obtaining the coordinates of step ₃ .

This makes it possible to install markers even in locations where there are obstacles such as tree canopies above, making it possible to efficiently perform marker installation work.

However, as mentioned above, when acquiring the coordinates of a marker by transit, the coordinates of the marker cannot be determined unless the coordinates of the point where the transit is installed are determined, so it is necessary to acquire the coordinates of the transit. be. The method of acquiring the transit coordinates is also not particularly limited. However, similar to the case of acquiring the marker coordinates described above, if the coordinates are acquired by GPS, it becomes difficult to install a transit in a place where it is difficult to acquire GPS coordinates because the upper part is covered with a tree canopy. Therefore, it is preferable that the coordinates of the transit are also obtained by measurement using the transit, as described below, instead of using GPS.

That is,
Prior to scanning with a 3D scanner,
a reference point setting step of setting a reference point in or near the measurement target area;
performing in advance a reference point coordinate acquisition step of acquiring the coordinates of the reference point in the one coordinate system;
In the transit coordinate acquisition step when acquiring the three-dimensional terrain data _D1 , by measuring the reference point with the transit, the coordinates of the point where the transit is installed in the one coordinate system are acquired;
In the subsequent transit coordinate acquisition process when acquiring the three-dimensional terrain data _D2 to _DN , the transit coordinates are acquired using the same procedure as the transit coordinate acquisition process when acquiring the three-dimensional terrain data _D1 . is preferred.

Here, ``In the subsequent transit coordinate acquisition process when acquiring three-dimensional terrain data D _{2 to D} Specifically, when _n is an integer greater than or equal to 2 and less than or equal to This means that the coordinates of the point where the transit is installed in the one coordinate system are obtained.

This makes it possible to install the transit even in locations where there are obstacles such as tree canopies above, making it possible to efficiently install the transit.

In the topographic measurement method of the present invention, the markers installed in the marker installation step are not particularly limited as long as they can be identified from the surrounding scenery, but
A support for standing on the ground,
It is preferable to use a marker display section disposed on the upper part of the support column and provided with a coordinate acquisition point whose coordinates are acquired in the marker coordinate acquisition step.

In this way, by disposing the marker display part (the part recognized by the three-dimensional scanner) of the marker on the top of the support column, the marker display part can be disposed at a higher location than the ground. Therefore, even if there are undulations or obstacles in the measurement target area, it is possible to make the marker display section visible even from a distance. Therefore, it becomes possible to measure a wide range of areas with a 3D scanner installed at a certain location, and it becomes possible to reduce the number of areas that need to be measured with a 3D scanner. Therefore, it is also possible to perform topographical measurements more efficiently.

At this time, the marker (a topographic measurement marker installed on the ground when measuring the topography by scanning with a three-dimensional scanner) is set so that the orientation of the marker display section is horizontal without moving the position of the coordinate acquisition point on the marker display section. Preferably, it can be adjusted both in the direction and in the vertical direction. More specifically,
marker,
A support for standing on the ground,
a marker display section disposed on the top of the support column and provided with a coordinate acquisition point from which coordinates are acquired in a marker coordinate acquisition step;
a horizontal angle adjustment mechanism for adjusting the orientation of the marker display section in the horizontal direction;
and a vertical angle adjustment mechanism for adjusting the orientation of the marker display section in the vertical direction,
The coordinate acquisition point is arranged at a location in the marker display section where a center line of rotation of the marker display section caused by the horizontal angle adjustment mechanism and a center line of rotation of the marker display section caused by the vertical angle adjustment mechanism intersect. is preferred.

This is because, although it is preferable for the marker display section to directly face the three-dimensional scanner or transit, there may be situations where it is desired to adjust the orientation of the marker display section at the measurement site. In addition, if the coordinate acquisition point in the marker display section moves when the orientation of the marker display section is adjusted, an error will occur in the coordinates of the marker obtained during transit, etc., but even if the orientation of the marker display section is changed, It is also possible to prevent such errors from occurring by preventing the position of the coordinate acquisition point from moving.

As described above, the present invention makes it possible to provide a terrain measurement method that can easily synthesize a plurality of three-dimensional terrain data. In addition, even if it is later discovered that 3D topographic data for an area that required 3D topographic data was not acquired, the 3D topographic data for that area can be transferred to the 3D scanner. This also makes it possible to provide a topographic measurement method that allows easy re-measurement. Furthermore, it is also possible to provide a terrain measurement method that does not require a three-dimensional scanner or the acquisition of GPS coordinates of points where markers are installed. Furthermore, it is also possible to provide a topographical measurement marker that can be suitably used when carrying out such a topographical measuring method.

1 is a diagram showing an example of three-dimensional terrain data obtained by the terrain measurement method of the present invention. 1 is a flowchart showing an example of the basic flow of the topographic measurement method of the present invention. FIG. 3 is a diagram showing an example of the order in which three-dimensional terrain data is acquired in the terrain measurement method of the present invention. 2 is a flowchart showing an example of a flow when acquiring three-dimensional terrain data _D1 in the terrain measurement method of the present invention. FIG. 2 is a perspective view showing an example of a marker used in the topographic measurement method of the present invention. FIG. 3 is a perspective view showing another example of a marker used in the topographic measurement method of the present invention. FIG. 7 is a perspective view showing a state in which the marker display section of the marker in FIG. 6 is rotated by 180 degrees around a horizontal axis _L1 . It is a flowchart which showed an example of the flow of a marker coordinate acquisition process in the terrain measurement method of the present invention. 2 is a flowchart showing an example of the flow of a transit coordinate acquisition step in the topography measurement method of the present invention. FIG. 3 is a diagram illustrating a scanning process in the topography measurement method of the present invention. FIG. 3 is a diagram showing how a three-dimensional terrain data synthesis step is performed in the terrain measurement method of the present invention.

A preferred embodiment of the topographic measurement method of the present invention will be described in more detail with reference to the drawings. The technical scope of the topographic measurement method of the present invention is not limited to the embodiments described below, and can be appropriately modified without departing from the spirit of the present invention.

1. Basic flow of the topography measurement method of the present invention FIG. 1 is a diagram showing an example of three-dimensional topography data D obtained by the topography measurement method of the present embodiment. In FIG. 1, the measured three-dimensional shape of the burial mound is shown as three-dimensional topographical data D. In the following, for convenience of explanation, the topographical measurement method of the present invention will be explained using as an example the case where the three-dimensional shape of a burial mound shown in FIG. 1 is measured. However, the use of the topographic measurement method of the present invention is not limited to the investigation of ancient tombs, but can be suitably employed in various uses.

FIG. 2 is a flowchart showing an example of the basic flow of the topography measurement method of the present invention. In the terrain measurement method of this embodiment, as shown in steps S100, S200, S300, S400, and _S500 in _FIG . I will continue to acquire it. That is, after acquiring 3D terrain data D ₁ , 3D terrain data D ₂ is acquired, and after acquiring 3D terrain data D ₂ , 3D terrain data D ₃ is acquired, and so on. This process is repeated until the three-dimensional terrain data _DN (Nth three-dimensional terrain data _DN ) is obtained.

The work of acquiring the three-dimensional terrain data D ₁ to D _N is performed by bringing a predetermined instrument (such as a three-dimensional scanner) to the site (measurement target area) and performing measurements, as will be described later. Therefore, in cases where the measurement work can be divided into multiple groups and performed in parallel, it is not necessary to acquire the three-dimensional terrain data D ₁ to D _N one by one, but multiple pieces can be acquired in parallel. You can also obtain them. When the last three-dimensional terrain data D _N (Nth three-dimensional terrain data D _N ) is acquired, as shown in step 600 in FIG. 2, the acquired N pieces of three-dimensional terrain data D ₁ to D _N is combined to generate combined data D. This composite data D corresponds to the three-dimensional terrain data D shown in FIG.

The three-dimensional terrain data acquisition step S300 and the three-dimensional terrain data synthesis step S600 in FIG. 2 will be described in detail below.

2. Three-dimensional terrain data acquisition process FIG. 3 is a diagram showing an example of the order of acquisition of three-dimensional terrain data in the terrain measurement method of the present invention. The three-dimensional topographic data acquisition process involves acquiring N pieces of three-dimensional topographic data D corresponding to each of N areas α ₁ to α _N (four areas α ₁ to α ₄ in the example of FIG. 3) in the measurement target area. ₁ to D _N (in the example of FIG. 3, four three-dimensional terrain data D ₁ to D ₄ ) are acquired. Therefore, in the three-dimensional topographic data acquisition process, from obtaining three-dimensional topographic data _D1 of area _α1 to obtaining three-dimensional topographic data _D1 of area _αN (in the example of FIG. 3, three-dimensional topographic data DN of area _α4 ). There are N steps (four steps in the example of FIG. 3) up to the one that acquires the terrain data D ₄ ).

That is, the measurement target area is divided into N areas α ₁ to α _N , and measurement is first performed in area α ₁ to obtain three-dimensional terrain data D ₁ , and then measurement is performed in area α ₂ to obtain the three-dimensional topographic data D 1. Obtain the three-dimensional topographical data _D2 of _α2 , and then sequentially measure in the areas _α3 to _αN-1 to obtain the three-dimensional topographical data _D3 to _DN-1 of the areas _α3 to αN _-1. Finally, measurement is performed in the area _αN to obtain three-dimensional terrain data _DN of the area _αN .

The number of areas into which the measurement target area is divided (the value of N above; hereinafter, it may be referred to as "the number of divisions N of the measurement target area") is not particularly limited as long as it is 2 or more. . The number of divisions N of the measurement target area usually increases as the measurement target area becomes wider, the degree of ups and downs becomes more severe, or the more obstacles there are. In the terrain measurement method of this embodiment, for convenience of explanation, the number of divisions N of the measurement target area is set to 4, but the number of divisions N of the measurement target area may be 5 or more, 10 or more, 15 or more, or 20 or more. However, it is possible to deal with it.

On the other hand, although there is no particular upper limit to the number of divisions N of the measurement target area, it is usually set to 1000 or less. In the topography measurement method of this embodiment, the number of divisions N per unit area (1 are) of the measurement target area may be set to 1 or less, 0.5 or less, or 0.3 or less. , 0.1 or less, or 0.05 or less. Depending on the topography, the performance of the three-dimensional scanner described below, etc., it is possible to set the number of divisions N per area of the measurement target area to 0.01 or less (one area is 100 areas or more).

In the terrain measurement method of this embodiment, each of the three-dimensional terrain data D ₁ to D ₄ is acquired as follows. First, a method for acquiring the three-dimensional terrain data _D1 will be explained. FIG. 4 is a flowchart showing an example of the flow when acquiring three-dimensional terrain data _D1 in the terrain measurement method of the present invention. As shown in FIG. 4, the three-dimensional terrain data _D1 is acquired through a marker installation step S320, a marker coordinate acquisition step S330, and a scanning step S340.

2.1 Marker installation process As shown in FIG. 3, the marker installation process S320 is performed at at least three points P _1.1 , P _1.2 , P _1.3 in area α ₁ in the measurement target area, as shown in FIG. This is the step of installing the marker 10 shown in . FIG. 5 is a perspective view showing an example of the marker 10 used in the topographic measurement method of the present invention. In the topographical measurement method of this embodiment, the points P _1.1 , P _1.2 , and P _1.3 at which the markers 10 are provided are all located on the ancient tomb that is the object to be measured (area indicated by hatching in FIG. 3). Although it is arranged above, it is not limited to this, and it can also be arranged in the surrounding area of the object to be measured.

As will be described later, the coordinates of the point where the marker 10 is placed (coordinates of points P _1.1 , P _1.2 , P _1.3 ) are measured. This marker 10 is also identified as a feature point on the three-dimensional topographical data _D1 , and the measured coordinates are given. That is, the marker 10 is important for giving coordinates to three different points in the three-dimensional terrain data _D1 . In this way, by determining the coordinates of three different points in the three-dimensional topographic data _D1 , the position and orientation of the three-dimensional topographic data _D1 in the coordinate system can be uniquely determined.

The three points P _1.1 , P _1.2 , P _1.3 at which the markers 10 are installed are selected as discrete points that are not on the same straight line. As will be described later, the markers 10 installed in the area α ₁ are required to be placed at locations within the field of view of the three-dimensional scanner installed at the point S ₁ (FIG. 3). In addition, in the topography measurement method of this embodiment, all of the markers 10 installed in the area α ₁ are required to be placed at locations where they can be measured by the transit installed at the point Q ₁ (FIG. 3). Ru.

In this regard, in the topographic measurement method of this embodiment, the marker 10 is composed of a support 11 for standing on the ground and a marker display section 12 supported on the top of the support, as shown in FIG. using things. The marker display section 12 is a part that can be recognized by the three-dimensional scanner 20, as shown in FIG. Even if there are obstacles such as trees or weeds or undulations between the marker display section 12 and the three-dimensional scanner 20, the three-dimensional scanner 20 can read the marker display section 12. .

The height H (FIG. 5) from the lower end of the support column 11 to the center C of the marker display section 12 in the marker 10 is not particularly limited. However, if the height H is made too low, the marker display section 12 cannot be supported at a high position. Therefore, the height H is usually 30 cm or more. The height H is preferably 50 cm or more, more preferably 70 cm or more, and even more preferably 90 cm or more. On the other hand, if the height H is set too high, the marker 10 may become large and difficult to carry and install. Therefore, the height H is usually 300 cm or less. The height H is preferably 250 cm or less, more preferably 200 cm or less. In the topographic measurement method of this embodiment, the height H is 100 cm.

The marker display section 12 of the marker 10 is provided with a display that can be identified by the three-dimensional scanner 20 (FIG. 10). The display on the marker display section 12 is usually a pattern or color that stands out from the surrounding scenery. In the topographic measurement method of this embodiment, the rectangular marker display section 12 is divided into rectangular sections of 2 rows and 2 columns, and a pattern in which white and black are alternately arranged in each section is used as the above display. are giving. The three-dimensional scanner 20 can easily identify this pattern even if the pattern is located in front of the ground, trees, weeds, rocks, or the sky.

By the way, in the conventional topographical measurement method, in order to efficiently install the marker 10, it is necessary to carefully examine and determine the location where the marker 10 is to be installed during a preliminary reconnaissance or the like. However, if the points P _1.1 , P _1.2 , and P _1.3 where the markers 10 are installed are far apart from each other, there is a risk that one of them will not come into the field of view of the three-dimensional scanner installed at the point S ₁ . , there is a possibility that the transit installed at point _Q1 will not be able to measure any of them. For this reason, in practice, the distances between the points P _1.1 , P _1.2 , and P _1.3 have been shortened for safety reasons.

However, if the distance between the points P _1.1 , P _1.2 , and P _1.3 is shortened, the markers 10 will be installed unevenly only in a narrow range in the area α ₁ , and the third There is a possibility that the accuracy of determining the position and orientation of the original terrain data _D1 may be reduced. In addition, it is no longer possible to secure a wide area _α1 , and measurements must be performed in many areas in order to obtain the three-dimensional shape of the entire measurement target area (three-dimensional topographical data necessary to obtain composite data D). There is also a risk that the number of

In contrast, in the topographic measurement method of this embodiment, as described above, the marker display section 12 is supported on the upper part of the support column 11 as the marker 10, and the marker display section 12 is recognized from a wide range. (visual recognition). Therefore, in the topographical measurement method of this embodiment, not only can the installation location of the marker 10 be easily determined, but also the number of areas to be measured can be kept small in order to obtain the three-dimensional shape of the entire measurement target area. It becomes.

Although the marker 10 may be installed so that its support 11 is inclined with respect to the vertical direction (the direction of gravity), it is usually installed so that its support 11 is parallel to the vertical direction. In the topography measuring method of this embodiment, a level (not shown) is attached to the marker 10 for confirming the direction of the support 11. The support column 11 of the marker 10 can be maintained in a vertical direction by a marker support means 40 (see FIG. 6) such as a tripod.

In addition to the marker 10 shown in FIG. 5, it is also preferable to use one shown in FIG. 6. FIG. 6 is a perspective view showing another example of the marker 10. The marker 10 in FIG. 6 includes a horizontal angle adjustment mechanism 14 and a vertical angle adjustment mechanism 13.

The horizontal angle adjustment mechanism 14 adjusts the vertical axis L of the marker display section ₁₂ by rotating the marker display section 12 in the left-right direction (in the direction of arrow _A3 or arrow _A4 in FIG. 6) about the vertical axis L2. It is possible to adjust the angle in _two directions (horizontal angle). That is, if the laser beam emitted from the three-dimensional scanner 20 is made to enter the front surface of the marker display section 12 substantially perpendicularly, the front surface of the marker display section 12 will be easily recognized by the three-dimensional scanner 20. By rotating the marker display section 12 in the left-right direction, the front surface of the marker display section 12 can be adjusted to be perpendicular or nearly perpendicular to the laser beam emitted from the three-dimensional scanner 20. It looks like this.

The specific configuration of the horizontal angle adjustment mechanism 14 is not particularly limited as long as it can perform the above functions. In the marker 10 of FIG. 6, the horizontal angle adjustment mechanism 14 is composed of a clamp 14a that is fitted onto the upper end of the support 11 and grips the upper end of the support 11, and a clamp operation means 14b that operates the clamp 14a. There is.

In this horizontal angle adjustment mechanism 14, when the clamp operating means 14b is operated to loosen the clamp 14a, the portion of the marker 10 above the clamp 14a (marker display section 12) is rotated in the left-right direction with respect to the column 11, While the horizontal angle of the marker display section 12 can be adjusted, when the clamp operation means 14b is operated to tighten the clamp 14a, the portion of the marker 10 above the clamp 14a (the marker display section 12) is moved against the support 11. The horizontal angle of the marker display section 12 can be fixed by preventing it from rotating in the left and right directions.

On the other hand, the vertical angle adjustment mechanism 13 rotates the marker display section 12 in the vertical direction (in the direction of arrow _A1 or arrow _A2 in FIG. ₆ ) about the horizontal axis L1. The angle around the axis _L1 (vertical angle) can be adjusted. That is, as already mentioned, if the laser beam emitted from the three-dimensional scanner 20 is made to enter the front surface of the marker display section 12 substantially perpendicularly, the front surface of the marker display section 12 will be easily recognized by the three-dimensional scanner 20. In the marker 10 of FIG. 6, by rotating the marker display section 12 in the vertical direction, the front surface of the marker display section 12 is made perpendicular or nearly perpendicular to the laser beam emitted from the three-dimensional scanner 20. It can be adjusted to.

The vertical angle adjustment mechanism 13 is not particularly limited in its specific configuration as long as it can perform the above functions. The marker 10 in FIG. 6 includes a support frame 13a which is shaped like a "U" in front view and which is fixed to the upper end of the support column 11 (the upper part of the clamp 14a), and a pair of left and right support frames 13a arranged on both sides of the marker display section 12. The left and right arm portions of the support frame 13a are rotated with respect to the side plate portions 13b, the connecting shaft portion 13c that connects the side plate portions 13b to each other and is fixed to the back side of the marker display portion 12, and the left and right arm portions of the support frame 13a relative to the left and right side plate portions 13b. The vertical angle adjustment mechanism 13 is constituted by the supporting shaft portion 13d that is movably connected and the tightening means 13e that tightens the support section 13d.

In this vertical angle adjustment mechanism 13, when the tightening means 13e is loosened, the side plate part 13b can be rotated with respect to the support frame 13a, so that the marker display part 12 can be rotated in the vertical direction. While the vertical angle can be adjusted, when the tightening means 13e is tightened, the vertical angle of the marker display section 12 can be fixed by preventing the side plate section 13b from rotating with respect to the support frame 13a. There is.

However, in the marker 10 shown in FIG. 6, if the coordinates of the center C of the front surface of the marker display section 12 change when adjusting the horizontal angle or vertical angle of the marker display section 12, the marker display section 12 will be 12, an error may occur in the position of the center C of the marker display section 12, and when measuring the coordinates of the marker display section 12 in transit, an error may occur in the coordinates of the center C of the marker display section 12. There is a possibility that accurate three-dimensional topographical data D of the measurement target area cannot be obtained.

In this regard, in the marker 10 shown in FIG. 6, the vertical axis _L2 and the horizontal axis _L1 intersect, and the center C of the marker display section 12 is located at the intersection of the vertical axis _L2 and the horizontal axis _L1 . I'm trying to locate it. Therefore, the horizontal angle of the marker display section 12 can be adjusted by rotating the marker display section 12 around the vertical axis _L2 , or the vertical angle of the marker display section ₁₂ can be adjusted by rotating the marker display section 12 around the horizontal axis L1. The position of the center C of the marker display section 12 is kept unchanged when the marker display section 12 is adjusted.

Further, in the marker 10 shown in FIG. 6, as shown in FIG. 7, a light reflecting part 12a is provided at the center of the back surface of the marker display part 12. FIG. 7 is a perspective view showing the marker display section 12 of the marker 10 of FIG. 6 rotated by 180 degrees around the horizontal axis _L1 .

This is because the marker 10 is the object of transit measurement in the marker coordinate acquisition step S330 (FIG. 4), which will be described later. This is because measurement can be made easier. The light reflecting section 12a is not particularly limited as long as it can reflect the light (usually laser light) emitted from the transit. The light reflecting section 12a can be provided by pasting a reflective sticker (not shown) on the back surface of the marker display section 12.

When the marker installation step S320 (FIG. ₄ ) is completed in the area α ₁ (the markers 10 are finished being installed at the points P _1.1 , P _1.2 , and P _1.3 in the area α 1 ), the marker installation step S320 (FIG. 4) is completed in the area α _{1 .} In step S330 (FIG. 4), marker coordinate acquisition step is performed.

2.2 Marker coordinate acquisition step The marker coordinate acquisition step S330 is a step of acquiring the coordinates of the points P _1.1 , P _1.2 , and P _1.3 where the markers 10 are installed in the area α ₁ . The coordinates of the points P _1.1 , P _1.2 , and P _1.3 where the markers 10 are installed can also be obtained by GPS, but in this case, the GPS coordinates may be It becomes difficult to install the marker 10 in a location that is difficult to obtain.

For this reason, in the topography measurement method of this embodiment, the coordinates of the points P _1.1 , P _1.2 , and P _1.3 where the markers 10 in the area α ₁ are installed are acquired by measurement using a transit. . Specifically, as shown in FIG. 8, the marker coordinate acquisition step S330 is performed by passing through a transit installation step S332, a transit coordinate acquisition step S333, and a marker coordinate measurement step S334. FIG. 8 is a flowchart showing an example of the flow of the marker coordinate acquisition process.

2.2.1 Transit installation process The transit installation process S332 is a process of installing a transit in or near area _α1 . In the topography measurement method of this embodiment, a transit is installed at point Q ₁ in FIG. 3, and the coordinates of points P _1.1 , P _1.2 , and P _1.3 in area α ₁ are acquired using this transit. ing. Point Q ₁ needs to be placed at a location where the marker display parts 12 of all the markers 10 installed at points P _1.1 , P _1.2 , and P _1.3 can be measured by the transit installed there.

By the way, a transit is a type of surveying instrument that measures angles, and is sometimes called a "theodolite" or a "theodolite." Some transits are equipped with light wave rangefinders (so-called total stations) that measure the distance to a target. If a total station is used as a transit, the distance and angle to the target can be measured at the same time, so the position of the marker 10 with respect to the transit can be easily and accurately measured. The topography measurement method of this embodiment also uses a total station as a transit.

2.2.2 Transit coordinate acquisition process The transit coordinate acquisition process S333 is a process of acquiring the coordinates of the point Q ₁ (FIG. 3) where the transit is installed. This transit coordinate acquisition step S333 is necessary for the following reasons. That is, the location where the transit is installed usually changes for each area α ₁ to α ₄ (for each three-dimensional terrain data D ₁ to D ₄ ). For this reason, each time the transit location is moved, unless the coordinates of the transit location are acquired, the relative positional relationship of the acquired three-dimensional terrain data D ₁ to D ₄ cannot be grasped. .

The coordinates of the transit (the coordinates of point _Q1 in Fig. 3) can also be obtained by GPS, but in this case, it is difficult to obtain the transit coordinates in a place where it is difficult to obtain GPS coordinates because the upper part is covered with a tree canopy. It becomes difficult to install. Therefore, it is preferable that the coordinates of a transit are obtained not by GPS but by measurement using the transit as described below.

That is, as shown in FIG. 9, the transit coordinate acquisition step S333 can be performed by passing through the reference point setting step S333.2, the reference point coordinate acquisition step S333.3, and the transit coordinate measuring step S333.4. preferable. FIG. 9 is a flowchart showing an example of the flow of the transit coordinate acquisition process.

2.2.2.1 Reference point setting step The reference point setting step S333.2 (FIG. 9) is a step of setting a reference point in or near the measurement target area. Reference points are usually installed at multiple locations. In the topography measurement method of this embodiment, reference points are set at points R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ in FIG. 3 so as to surround the burial mound that is the object to be measured. There is. As a reference point, a mirror pole, a prism pole, etc. used in conventional surveying can be used. These reference points are used as a reference when obtaining the coordinates of the points Q ₁ , Q ₂ , Q ₃ , and Q ₄ where the transits are installed. It is preferable that the reference point setting step S333.2 (FIG. 9) is performed in advance prior to the marker setting step S320 (FIG. 4) and the like described above.

The number of reference points (total number of points R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ ) varies depending on the size of the measurement target area and is not particularly limited. However, transits must be installed at locations where any one of the reference points can be measured, and if too few reference points are installed, there is a risk that the degree of freedom in arranging the transits will be reduced. Therefore, the number of installed reference points (denoted as N 2 ) with respect to the total number of markers 10 (denoted as _{N 1} ) installed in areas α ₁ to α _N (in the example of FIG. 3, areas α ₁ to α ₄ ) is calculated as follows: The ratio N ₂ /N ₁ is preferably 0.1 or more. The ratio N ₂ /N ₁ is more preferably 0.2 or more, and even more preferably 0.3 or more. However, if the number of reference points installed is too large, the effort required for the reference point coordinate acquisition step S333.3 (FIG. 9), which will be described later, will increase. Therefore, the ratio N ₂ /N ₁ is usually set to 1 or less.

2.2.2.2 Reference point coordinate acquisition process The reference point coordinate acquisition process S333.3 (FIG. 9) is performed at the points R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ ( This is the step of acquiring the coordinates of FIG. 3). The coordinates of the reference point can be acquired using GPS when the measurement target area is outdoors. Also in the terrain measurement method of this embodiment, the coordinates of the reference point are acquired by GPS. However, if there are obstacles above the measurement target area or if the measurement target area is indoors in a large facility such as a factory, it is not possible to obtain the coordinates of the reference point using GPS. There are cases.

The coordinate system representing the coordinates of this point and the reference point is the coordinates of the marker 10 (coordinates of points P _1.1 , P _1.2 , P _1.3, etc.) and the coordinates of the transit (coordinates of point Q ₁ , etc.) The coordinate system need not be an absolute coordinate system, such as a GPS coordinate system (a coordinate system consisting of latitude and longitude on the earth). Therefore, when performing the reference point coordinate acquisition step S333.3 in an environment where it is difficult to use GPS, such as indoors, the reference point coordinate acquisition step S333.3 is performed at the points R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ The relative position of is measured using a survey instrument such as a transit or tape measure, and the coordinate system defined by these reference points (points R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ ) It is preferable to obtain the coordinates of the marker 10 and the coordinates of the transit using the following.

2.2.2.3 Transit coordinate measurement process The transit coordinate measurement process S333.4 (Fig. 9) is performed at points R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ (Fig. 3). This is a process of measuring the coordinates of the transit at that time by measuring one of the plurality of reference points with the transit. In the topography measurement method of this embodiment, the position of point Q ₁ with respect to points R ₁ and R ₂ is measured by measuring the reference points installed at points R ₁ and R ₂ with a transit installed at point Q ₁ in FIG. In other words, the coordinates of the transit are measured. The coordinates of the transit can be determined using the backward intersection method.

When the transit coordinate measurement step S333.4 (FIG. 9) is completed, the transit coordinate acquisition step S333 (FIG. 8) is completed, and subsequently, the marker coordinate measurement step S334 (FIG. 8) is performed.

2.2.3 Marker coordinate measurement step The marker coordinate measurement step S334 (FIG. 8) is a measurement using a transit installed at point _Q1 to obtain the coordinates of points _P1.1 , _P1.2 , and _P1.3 . This is the process of As already mentioned, the coordinates of the point Q ₁ where the transit is installed are determined from the relationship with the reference points set _at points _{R 1} , R ₂ , etc. , P _1.3 , the coordinates of the points P _1.1 , P _1.2 , P _1.3 can be determined. When the marker coordinate measurement step S334 is completed, the marker coordinate acquisition step S330 (FIG. 4) is completed, and then the scanning step S340 is performed.

2.3 Scanning process In the scanning process S340 (Fig. 4), a three-dimensional scanner is installed at a point where all the markers placed at points P _1.1 , P _1.2 , P _1.3 (Fig. 3) come into view. As shown in FIG. 10, this is a step of scanning the surroundings of the three-dimensional scanner 20 (spatial measurement). FIG. 10 is a diagram showing how the scanning process is performed. In FIG. 10, for convenience of illustration, among the three markers 10 installed at points P _1.1 , P _1.2 , and P _1.3 in area α ₁ , the marker 10 installed at point P _1.3 is shown. Illustration is omitted.

When performing the scanning step S340 in the area α ₁ (FIG. 3) in the measurement target area, the scanner 20 usually locates near the center of the area α ₁ or at the point P _1.1 where the marker 10 is placed in the area α ₁ . It is installed inside the triangle formed by P _1.2 and P _1.3 . In the topography measuring method of this embodiment, when performing the scanning step in area _α1 , the scanner 20 is installed at point _S1 in FIG. Furthermore, when performing the scanning process in area α ₂ , the scanner 20 is installed at point S ₂ , and when performing the scanning process S340 in area α ₃ , the scanner 20 is installed at point S ₃ , and when performing the scanning process S340 in area α ₄ . When performing the scanning process, the scanner 20 is installed at point _S4 .

The three-dimensional scanner 20 is not particularly limited in type as long as it can measure the three-dimensional shape of the surrounding terrain, but it usually measures the three-dimensional shape by emitting light waves such as laser light. A scanning optical distance meter (so-called laser scanner) is used to measure the three-dimensional shape of the surrounding terrain.

Further, the maximum measurement distance of the three-dimensional scanner 20 varies depending on the width of the measurement target area α, and is not particularly limited. However, if the maximum measurement distance of the three-dimensional scanner 20 is too short, in order to measure the three-dimensional shape of almost the entire area of the measurement target area, it becomes necessary to divide the measurement target area into more areas, which reduces the scanning process. The number of areas that must be covered increases. Therefore, the maximum measurement distance of the three-dimensional scanner 20 is usually 10 m or more. The maximum measurement distance of the three-dimensional scanner 20 is preferably 30 m or more, more preferably 50 m or more, and even more preferably 100 m or more. The upper limit of the maximum measurement distance of the three-dimensional scanner 20 is not particularly limited, but is usually about 500 to 1000 m.

In the topography measurement method of this embodiment, a laser scanner manufactured by FARO Corporation, "FARO Laser Scanner Focus ^3D " (model: Focus ^3D X330), is used as the three-dimensional scanner 20. This three-dimensional scanner 20 has a maximum measurement distance of 330 m, a maximum measurement speed of 976,000 points/second, and a maximum range error of ±2 mm. Further, the laser beam emitting unit 21 (FIG. 10) in this three-dimensional scanner 20 can rotate (scan) in the direction of arrow A ₅ around the vertical axis L ₂ passing through point S ₁ . A range of 360° is included in the measurement range.

2.4 After finishing the scanning process of area α ₁ When the scanning process S340 (FIG. 4) is finished in area α ₁ , the 3D scanner 20 has acquired the 3D topographical data D ₁ of area α ₁ . It becomes. When the three-dimensional terrain data D ₁ is acquired, other three-dimensional terrain data D ₂ , D ₃ , and D ₄ are also acquired (see steps S300, S400, and S500 in FIG. 2). The three-dimensional topographical data D ₂ , D ₃ , D ₄ of the other areas α ₂ , α ₃ , α ₄ are obtained in the same procedure as the three-dimensional topographical data D ₁ of the area α ₁ .

However, in the topography measurement method of this embodiment, when acquiring the three-dimensional topography data D ₂ of the area α ₂ , markers installed at points P _2.1 , P _2.2 , P _2.3 in FIG. is scanned by a three-dimensional scanner installed at point _S2 in the figure, and when acquiring three-dimensional topographical data _D3 of area _α3 , points _P3.1 , P3.1 in FIG _{. 2} , P _3.3 is scanned by a 3D scanner installed at point S ₃ in the same figure, and when acquiring 3D topographical data D ₄ of area α ₄ , Markers placed at points P _4.1 , P _4.2 , and P _4.3 in the figure are scanned by a three-dimensional scanner placed at point S ₄ in the figure. Among areas α ₁ , α ₂ , α ₃ , α ₄ , adjacent areas share some markers (for example, in the area where area α ₁ and area α ₂ overlap in FIG. For example, point P _1.2 and point P _2.1 may be placed at the same location.

In addition, in the topography measurement method of this embodiment, the coordinates of points P _2.1 , P _2.2 , P _2.3 where markers are installed within area α ₂ are the coordinates of points P 2.1 , P 2.2 , and P _2.3 where markers are installed within area α 2. The coordinates _of points P _3.1 , P _3.2 , and P _3.3 , which were acquired at point _{Q 3 in} FIG. The coordinates of points P _4.1 , P _4.2 , and P _4.3 where the markers were placed are acquired by the transit placed at point Q ₄ in FIG. 3. If all markers belonging to two or more areas come into view from a transit placed at any of points Q ₁ , Q ₂ , Q ₃ , or Q ₄ , the transit may not be moved in those areas. It is also possible to obtain the coordinates of the markers in those areas by measuring from the same point instead.

Furthermore, in the terrain measurement method of this embodiment, the coordinates of the transit installed at point Q ₂ are obtained by collimating the reference points installed at _points R ₃ and R ₄ from the transit, and The coordinates of the installed transit are obtained by collimating the reference points installed at points R ₄ and R ₅ from that transit, and the coordinates of the transit installed at point Q ₄ are obtained by collimating the reference points installed at points R ₁ and R ₆ from that transit. Although the information is acquired by sighting at a reference point set at , it is not limited to this. The coordinates of the transit can be obtained using any reference point that can be sighted by the transit installed at that point.

When the scanning step S340 (FIG. ₄ ) is completed for all areas _{α 1 to} α ₄ and all three-dimensional topographical data D 1 to D 4 of areas α ₁ to α ₄ are acquired (“YES” in step S400 in FIG. 2), ''), then a three-dimensional terrain data synthesis step S600 is performed.

3. 3D terrain data synthesis step The terrain data synthesis step synthesizes the 3D terrain data D ₁ to D ₄ acquired in the above-mentioned 3D terrain data acquisition step S300 (FIG. 2) to obtain data covering almost the entire area in the measurement target area. This is a step of obtaining three-dimensional topographical data D (see FIG. 1). FIG. 11 is a diagram showing how the three-dimensional terrain data synthesis process is performed. In the topography measurement method of this embodiment, when all the three-dimensional topography data acquisition steps S300 described above have been completed, not only the three-dimensional topography data D ₁ to D ₄ shown in FIG. 11 have been acquired, but also the three-dimensional topography In each of the data D ₁ to D ₄ , the coordinates of at least three points where markers are placed have been acquired.

Therefore, as shown in FIG. 11, the points P _1.1 , P _1.2 , P where markers are placed within the area α ₁ are located in a common coordinate system (xyz coordinate system in the example shown in the figure). Coordinates of _1.3 , points P _2.1 , P _2.2 , P _2.3 where markers are placed within area α ₂ , points P _3.1 , P ₃ where markers are placed within area α _{3 .2} , P _3.3 coordinates and the coordinates of points P _4.1 , P _4.2 , P _4.3 where markers were installed in area α ₄ are plotted, and three-dimensional topographical data of area α ₁ is obtained. The three points where the marker was identified in _D1 overlap the points _P1.1 , _P1.2 , _P1.3 in the first coordinate system, and the marker is identified in the three-dimensional terrain data _D2 of the area _α2 . The three identified points overlap the points P _2.1 , P _2.2 , and P _2.3 in the one coordinate system, respectively, and the three identified markers in the three-dimensional terrain data D ₃ of the area α ₃ The points overlap points P _3.1 , P _3.2 , and P _3.3 in the first coordinate system, respectively, and the three points for which markers have been identified in the three-dimensional topographical data D ₄ of area α ₄ are in the first coordinate system. By simply superimposing the three-dimensional terrain data D ₁ to D ₄ on the one coordinate system so as to overlap the points P _4.1 , P _4.2 , and P _4.3 in the coordinate system, the composite data shown in FIG. 1 can be created. D is generated.

This three-dimensional topographical data synthesis step is usually performed on a computer. Even if the synthesis work requires manual intervention, the work is limited to the work of identifying points where markers are identified in the three-dimensional topographical data D ₁ to D ₄ and the work of inputting the coordinates of the points. Therefore, human error is less likely to occur in the synthesis work. Further, even if a human error occurs, by looking at the composite data D, it is possible to easily understand in which part the error has occurred, and to quickly correct it.

By the way, although it is okay for the synthesized data D (Fig. 1) to have missing areas (even if there are gaps in the 3D topographical data D ₁ to D ₄ after synthesis), it is preferable to avoid missing areas as much as possible. It is preferable that it be in a continuous state. The missing area is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less of the total area of the measurement target area. In the terrain measurement method of this embodiment, even if it is found that there is a missing area after generating the three-dimensional terrain data D, the missing area can be remeasured relatively easily.

4. Others The composite data D (Figure 1) is created by removing obstacles such as trees, weeds, or rocks from the three-dimensional terrain data D ₁ to D ₄ acquired as digital data in the above-mentioned scanning process S340 (Figure 4). It can also be removed (digitally). Thereby, the composite data D can be made to be one that does not include obstacles (substantially only the ground surface is represented). This process (hereinafter sometimes referred to as "obstacle removal process") may be performed at any timing after the scanning step S340. However, if the obstacle removal process is performed before performing the three-dimensional terrain data synthesis step S600, the obstacle removal process for the overlapping portions of the three-dimensional terrain data D ₁ to D ₄ will be performed redundantly, and the Efficient. Therefore, it is preferable that the obstacle removal process is performed after the three-dimensional terrain data synthesis step S600 is completed.

Although the specific method (software) for obstacle removal processing is not particularly limited, it is usually performed using a three-dimensional point cloud that can process point cloud data acquired in three dimensions (three-dimensional point cloud data). Data processing software is used. In the terrain measurement method of this embodiment, obstacle removal processing is performed on a personal computer using the noise removal function (ground extraction function) of the three-dimensional point cloud data processing software "InfiPoints" manufactured by Elysium.

5. Purpose
By using the topographical measurement method of this embodiment, it is possible to suppress the error in the three-dimensional topographical data D (see FIG. 2) of the measurement object (measurement target area) to about several mm. The original topographical data D can be effectively utilized for various analyzes and various studies of measurement objects. For example, from the three-dimensional topographical data D of a tumulus, it is possible to not only obtain basic information such as the size and shape of a tumulus and its orientation, but also to identify with high precision the marks where the ground has been scraped and the places where soil has been piled up. This makes it possible to obtain detailed information such as traces of grave theft.

The topography measurement method of the present invention can be effectively used not only for investigating ancient tombs, but also in various fields such as civil engineering, such as investigating planned construction sites for golf courses and dam construction sites. Furthermore, the topography measurement method of the present invention can be used not only outdoors but also when measuring the three-dimensional shape of an indoor space. For example, it can be used to investigate the current condition of buildings such as factories (investigating whether there are any problems such as cracks in walls or ceilings, investigating the location of piping, etc.).

10 Marker 11 Support 12 Marker display section 12a Light reflecting section 13 Vertical angle adjustment mechanism 13a Support frame 13b Side plate section 13c Connection shaft section 13d Support shaft section 13e Tightening means 14 Horizontal angle adjustment mechanism 14a Clamp 14b Clamp operation means 20 Three-dimensional scanner 21 Laser light emitting unit 40 Marker support means D Three-dimensional terrain data (after synthesis)
D ₁ to D ₄ 3D terrain data (before synthesis)
P ₁ to P ₄ Points to install markers Q ₁ to Q ₄ Points to install transits R ₁ to R ₆ Points to install reference points S ₁ to S ₄ Points to install 3D scanners α ₁ to α ₄ areas ( measurement target area)

Claims (3)

By combining multiple pieces of 3D topographical data D ₁ to D _N (N is an integer greater than or equal to 2) obtained by scanning with a 3D scanner, 3D data can be obtained over approximately the entire area covered by the tree canopy. A topographic measurement method for obtaining original topographic data,
Three-dimensional terrain data _D1 ,
A marker installation step of installing markers at at least three points P _1.1 , P _1.2 , P _1.3 in the area corresponding to the three-dimensional topographical data D ₁ in the measurement target area;
a marker coordinate acquisition step of acquiring the coordinates of points P _1.1 , P _1.2 , P _1.3 in one coordinate system;
A three-dimensional scanner is installed at a point where all the markers installed at points P _1.1 , P _1.2 , P _1.3 come into view, and the area around the three-dimensional scanner is scanned.
The subsequent three-dimensional terrain data _D2 to _DN are also obtained through the same process as the three-dimensional terrain data _D1 ,
The three-dimensional terrain data D ₁ to D _N are arranged in the first coordinate system based on the coordinates of the markers acquired in the respective marker coordinate acquisition steps when acquiring the three-dimensional terrain data D ₁ to D _N. In this way, the three-dimensional terrain data D ₁ to D _N are synthesized , and
Prior to scanning with a 3D scanner,
a reference point setting step of installing a plurality of reference points in locations not covered by tree canopies in or near the measurement target area;
a reference point coordinate obtaining step of obtaining coordinates of the plurality of reference points in the one coordinate system using GPS;
Do this in advance,
The marker coordinate acquisition process when acquiring three-dimensional terrain data D1 is as follows _:
a transit installation step of installing a transit in or near an area corresponding to three-dimensional topographical data D1 _;
a transit coordinate acquisition step of acquiring the coordinates of a point where the transit is installed in the one coordinate system by measuring one of the plurality of reference points with the transit;
a marker coordinate measuring step of acquiring the coordinates of points P _1.1 , P _1.2 , and P _1.3 in the one coordinate system by measurement using a transit;
done by going through
The subsequent marker coordinate acquisition step and transit coordinate acquisition step when acquiring the three-dimensional terrain data D ₂ to D _N are also the same as the marker coordinate acquisition step and transit coordinate acquisition step when acquiring the three-dimensional terrain data D ₁ , respectively. Do it through similar steps
A terrain measurement method characterized by:
As a marker installed in the marker installation process,
A support for standing on the ground,
2. The terrain measuring method according to claim 1 , comprising: a marker display section disposed on the top of the support column and provided with a coordinate acquisition point whose coordinates are acquired in the marker coordinate acquisition step.
3. The topography measuring method according to claim 2 , wherein the marker installed in the marker installation step is one whose orientation of the marker display section can be adjusted in the horizontal and vertical directions without moving the position of the coordinate acquisition point on the marker display section.

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